function squ = Skel( I2,ds )
% I2 Image channel 2 Fret Intensity cast unit16
% ds Disk size for Structurant element 4 or 5
% retourne le 'Squelette' 


% Element Structurant
e=strel('disk',ds);

% Seuillage
[level] = graythresh(I2);

% Image Binaire
bin=im2bw(I2,level);


% Inverse 
bin=1-bin;

% Ouverture
bin = imopen(bin,e);

% Fermeture
bin = imclose(bin,e);
bin=1-bin;

% Squelette
squ=bwmorph(bin,'thin',Inf);

end