.NTI2NA.MjY4MDYx

that this prevents us from using measurements on individual objects). Until now we have not used this possibility, concen¬ trât ing mainly on intensity and size for which thresholding and opening are ideally adapted. 2/ Thresholding and Opening : natural size distributions* We define two transformations - thresholding at level \ : ^f(x) = | f(x) if f(x) > \ 0 otherwise f,iW = WX) - opening of size \x (it is the opening ofthe umbra of f by a cylinder of size X) . A t\ / t

Fig. 9 : 2 granulometrie transformations These two transformations both haye the same useful properties :

• increasing : f < g

xî s xg f ^ g

• antiextensiyity :

lf < f. f s f ,X2) X2,X1 \1 x2 ( 1 f) = ' C f) = sup(\1,\2) in particular idempotence s X(Xf) = xf (f ) = f M- V H