( ) ( ). ( ) , . cC rR gG bB= + + c r g b, , , ¹ 0 (cC ) 1 (cC ) 2 (cC + (cC ) = (rR + (rR ) + (gG + (gG ) + (bB + (bB ) 2 ) ) ) ) 2 1 1 2 1 2 1