function [E,contour,G_somme] = recursion(E,contour,G_somme,i,j,voisins,G_x,G_y,card_max,cos_alpha)
% Fonction recursive permettant de construire un ensemble candidat E

    contour(i,j) = 0;
    G_somme_normalise = G_somme/norm(G_somme);
    nb_voisins = size(voisins,1);
    k = 1;
    while k<=nb_voisins & size(E,1)<=card_max
        i_voisin = i + voisins(k, 1);
        j_voisin = j + voisins(k, 2);
        if contour(i_voisin,j_voisin)
            
            G_ij = [G_x(i_voisin, j_voisin), G_y(i_voisin, j_voisin)];
            G_ij_normalise = G_ij/norm(G_ij);
            
            prod_scal = G_somme_normalise*G_ij_normalise';
            
            if prod_scal >= cos_alpha
               
                E = [E; i_voisin j_voisin];
                G_somme = [G_somme; G_ij_normalise];
                recursion(E, contour, G_somme, i_voisin, j_voisin, voisins, G_x, G_y, card_max, cos_alpha);
                
            end
            
        end
        k = k+1;
    end
end