TP-modelisation-images/super_pixel.m

function germes = super_pixel(img, K, m, n, q_max)
    img = im2double(img);
%     img = img(1:10, 1:10, :);

    width = size(img, 1);
    height = size(img, 2);
    N = width * height;

    S = sqrt(N / K);
    X = S / 2:S:width;
    Y = S / 2:S:height;
    germes = zeros(length(X) * length(Y), 5);
    c = 1;

    for x = X

        for y = Y
            germes(c, :) = [x y 0 0 0];
            c = c + 1;
        end

    end

    scatter(germes(:, 2), germes(:, 1), 'g.');

    c = 1;

    for germe = germes'

        x = germe(1);
        y = germe(2);

        xmin = floor(max(x - n, 1));
        interval_x = xmin:min(x + n, width);

        ymin = floor(max(y - n, 1));
        interval_y = ymin:min(y + n, height);
        
        Gmag = imgradient(img(interval_x, interval_y));
        [~, ind_min] = min(Gmag(:));
        [nr, nc] = ind2sub(size(Gmag), ind_min);

        x = xmin + nr - 1;
        y = ymin + nc - 1;

        germes(c, :) = [x y img(x, y, 1) img(x, y, 2) img(x, y, 3)];

        c = c + 1;
    end

    scatter(germes(:, 2), germes(:, 1), 'r.');

    germe_per_pixel = zeros(width, height);

    for q = 1:q_max

        for x = 1:width

            for y = 1:height

                % initialisation des minimums
                min_Ds = 1e5;

                for index_germe = 1:length(germes)
                    germe = germes(index_germe,:);

                    % on récupère les coordonnées du germe
                    xg = germe(1);
                    yg = germe(2);

                    % on calcule la distance spatiale entre le germe et le pixel
                    Dxy = norm([x - xg y - yg]);

                    % si le germe est trop loin on skip
                    if Dxy > S
                        continue;
                    end

                    % on récupère les couleurs du germe
                    rg = germe(3);
                    gg = germe(4);
                    bg = germe(5);

                    % on récupère les couleurs du pixel
                    r = img(x, y, 1);
                    g = img(x, y, 2);
                    b = img(x, y, 3);

                    % on calcule la distance chromatique entre le germe et le pixel
                    Dlab = norm([r - rg g - gg b - bg]);

                    % on calcule Ds
                    Ds = Dlab + m / S * Dxy;

                    % Si Ds est meilleur on le prend
                    if Ds < min_Ds
                        germe_per_pixel(x, y) = index_germe;
                        min_Ds = Ds;
                    end

                end

            end

        end
        
        image(germe_per_pixel);
        colormap lines;

        for index_germe = 1:length(germes)
            truc = germe_per_pixel == index_germe;
            truc_rgb = reshape(img(repmat(truc,[1 1 3])), [], 3);
            m_rgb = mean(truc_rgb);
            mx = 0;
            my = 0;
            for i = find(truc == 1)'
                [x, y] = ind2sub(size(img), i);
                mx = mx + x;
                my = my + y;
            end
            mx = mx / sum(truc, 'all');
            my = my / sum(truc, 'all');
            germes(index_germe,:) = [mx my m_rgb];
        end

        scatter(germes(:, 2), germes(:, 1), 'b.');

    end

end