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Toolbox Fast Marching

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Toolbox Fast Marching


Gabriel Peyre (view profile)


24 Oct 2004 (Updated )

A toolbox for the computation of the Fast Marching algorithm in 2D and 3D.

% test for fast marching and geodesic extraction
%   Copyright (c) 2004 Gabriel Peyr

n = 600;
name = 'road2';
name = 'constant';
name = 'mountain';
[M,W] = load_potential_map(name, n);

rep = 'results/geodesic-2d/';
if not(exist(rep))

warning off;
imwrite(rescale(W), [rep name '-map.png'], 'png');
warning on;

% pick starting point
[start_points] = pick_start_end_point(M);

options.nb_iter_max = Inf;
disp('Performing front propagation.');
[D,S] = perform_fast_marching(W, start_points, options);

npaths = 30;
end_points = floor( rand(npaths,2)*(n-1) )+1;

disp('Extract paths');
paths = {};
for i=1:npaths
    paths{i} = compute_geodesic(D,end_points(:,i));
    if length(paths{i}(:))==2
        paths{i} = paths{i-1};

ms = 30; lw = 3;
% display
A = convert_distance_color(D);
clf; hold on;
imageplot(A); axis image; axis off;
for i=1:npaths
    end_point = end_points(:,i);
    h = plot( paths{i}(2,:), paths{i}(1,:), 'k' );
    set(h, 'LineWidth', lw);    
    h = plot(end_point(2),end_point(1), '.b');
    set(h, 'MarkerSize', ms);    
h = plot(start_points(2),start_points(1), '.r');
set(h, 'MarkerSize', ms);
hold off;
colormap jet(256);
axis ij;
saveas(gcf, [rep name '-geodesics.png'], 'png');

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