Thread Subject: Modified saturation

How can i modify a saturation of the image and i want to modify the saturation based on this equation. Plz help me to solve.

S(x, y) =1-(3/(R+G+B)[min(R,G,B)]) ---------------> 1
~S(x, y) = S(x, y)/max(S(x, y))
Max(S(x, y)) =2*(0.5-I(x, y)), if ~I(x, y)>0.5 ---------> 2
Max(S(x, y)) =I(x, y)), Otherwise. -------------------> 2

S(x, y) and Max(S(x, y)) denote the saturation value and the maximum saturation value at the corresponding intensity level, respectively ~I(x, y). Denotes the intensity at the (x, y), which is normalized to [0,1] . Based on the conical HSI color model, the maximum value of saturation is normalized in accordance with ~I(x, y) compared to 0.5 in (2)