function [cx21g,cy21g]=clique_points(nbpoints,im,cx21g,cy21g,D)

figure
for ni=1:nbpoints
    imagesc(im);
    axis image
    if ni>=2
        hold on
        plot(cx21g(1:ni,1),cy21g(1:ni,1),'r+')
        hold off
    end
    colormap(gray);
%     [x,y] = ginput(1);
%     axis([x-D x+D y-D y+D])
    [cx21g(ni),cy21g(ni)] = ginput(1);
end