The blurring is performed by the following equation: P ??? ??? S ??? ( x , y ) = P ??? ??? C ??? ( x , y ) ??? P ??? ??? T ??? ( x , y ) + ( 1 - P ??? ??? T ??? ( x , y ) ) ??? 1 ( k + 1 ) 2 ??? ??? m = - k 2 m = k 2 ??? ??? n = - k 2 n = k 2 ??? P ??? ??? Z ??? ( x + m , y + n ) k=K???PT(x,y) [0064] wherein K is a constant.