% test for active contours%%   Copyright (c) 2007 Gabriel Peyreoptions.bound = 'per';n = 32;d = ones(n); d = rand(n);d = repmat(d,[1 1 2]);D = zeros(n^2);for i=1:n^2    a = zeros(n); a(i)=1;    a = divgrad(divgrad(a,options)./d,options);    D(:,i) = a(:);endn = 150;path(path, 'data/');path(path, 'toolbox/');motion = 'affine';motion = 'errosion';motion = 'chan-vese';motion = 'mean';motion = 'snake';% load image for active contourname = 'chan-vese';name = 'disk';name = 'brain';M = rescale( sum( load_image(name, n), 3) );options.solver = 'grad';options.solver = 'cg';    %% load original shapeoptions.null = 0;if strcmp(motion, 'snake')    namec = 'square';    options.width = 0.95*n;elseif strcmp(motion, 'chan-vese')    namec = 'small-disks';else    namec = 'circlerect1';    namec = 'square';    namec = 'circlerect2';endD0 = compute_levelset_shape(namec, n);options.center = [0.15 0.15]*n;options.radius = 0.1*n;D1 = compute_levelset_shape('circle', n,options);%% set up the parametersoptions.Tmax = 1000;options.redistance_freq = 150;options.M = M;options.dt = 0.1;options.dt = 3;options.display_freq = 5;options.nb_svg = 100;if strcmp(motion, 'snake')    options.Tmax = 2000;    options.redistance_freq = 30;    options.dt = 1;    % compute edge-based energy    sigma = 4; % blurring size    G = divgrad( perform_blurring(M,sigma) );    G = sum( G.^2, 3);    eta = 0.01;    E = 1 ./ (eta + G);    options.E = rescale(E, 0.7, 1);elseif strcmp(motion, 'chan-vese')    options.redistance_freq = 30;    options.E = M;    options.lambda = 0.8;    options.update_c = 0;    options.c1 = 0;    options.c2 = 0.5;    options.dt = 0.2;    options.dt = 2;endD = perform_active_contour(D0, motion, options);