(ii) City Block Distance

(iii) Chessboard Distance

(iv) M-Connectivity

Consider 2 pixels P(x,y) and Q(s,t)

Euclidean Distance $D_e (P,Q)= \sqrt {(x-s)^2+(y-t)^2}$

CityBlockDistance $D_4 (P,Q)=|x-s|+|y-t|$

ChessboardDistance $D_8 (P,Q)=Max(|x-s|,|y-t|)$

M-connectivity: Two pixels P and Q with their values from {V} are said to be M-point connected if QϵN_4 (P) or QϵN_D (P)andN_4 (P)∩N_4 (Q)=∅.