function [moyennes,variances] = estimation_RVB(I,N,couleur_classes,fig)
%     fig3 = figure(3);
%     densR = ksdensity(reshape(255*I(:,:,1),1,[]),0:255);
%     densG = ksdensity(reshape(255*I(:,:,2),1,[]),0:255);
%     densB = ksdensity(reshape(255*I(:,:,3),1,[]),0:255);
% 
%     plot(0:255,densR,'r');
%     hold on;
%     plot(0:255,densG,'g');
%     plot(0:255,densB,'b');
%     plot(0:255,densR+densG+densB,'k');


    fprintf('Selectionnez %d echantillons\n',N);
    [nb_lignes,nb_colonnes,nbchannel] = size(I);
    
    moyennes = zeros(N,nbchannel);
    variances = zeros(N,nbchannel,nbchannel);
    coords = [  62.8251   22.2301   57.1851   16.3336;
                138.1969   95.5509  131.2750  101.9601;
                    80.0017  123.2385   88.7182  131.1859 ];
    for k = 1:N
        figure(fig);
        x1 = coords(k,1);
        y1 = coords(k,2);
        x2 = coords(k,3);
        y2 = coords(k,4);
% 	    [x1,y1] = ginput(1);
% 	    while (x1<1)||(x1>nb_colonnes)||(y1<1)||(y1>nb_lignes)
% 		    [x1,y1] = ginput(1);
%         end
% 	    [x2,y2] = ginput(1);
% 	    while (x2<1)||(x2>nb_colonnes)||(y2<1)||(y2>nb_lignes)||(x2==x1)||(y2==y1)
% 		    [x2,y2] = ginput(1);
%         end
%         x1y1x2y2 = [x1 y1 x2 y2]
	    line([x1,x1],[y1,y2],'Color',couleur_classes(k,:),'Linewidth',2);
	    line([x1,x2],[y2,y2],'Color',couleur_classes(k,:),'Linewidth',2);
	    line([x2,x2],[y2,y1],'Color',couleur_classes(k,:),'Linewidth',2);
	    line([x2,x1],[y1,y1],'Color',couleur_classes(k,:),'Linewidth',2);
	    drawnow;
    
	    echantillons = [];
	    for i = floor(min([y1,y2])):ceil(max([y1,y2]))
		    for j = floor(min([x1,x2])):ceil(max([x1,x2]))
                tmp(:) = I(i,j,:);
			    echantillons = [ echantillons ; tmp ];
		    end
        end

%         figure(k+10);
%         densR = ksdensity(reshape(255*echantillons(:,1),1,[]),0:255);
%         densG = ksdensity(reshape(255*echantillons(:,2),1,[]),0:255);
%         densB = ksdensity(reshape(255*echantillons(:,3),1,[]),0:255);
%     
%         plot(0:255,densR,'r');
%         hold on;
%         plot(0:255,densG,'g');
%         plot(0:255,densB,'b');
%         plot(0:255,densR+densG+densB,'k');

	    moyenne = mean(echantillons);
	    moyennes(k,:) = moyenne;
        covariances = cov(echantillons);
	    variances(k,:,:) = covariances;

end