How formula for saturation component is working in RGB-HSI conversion?

1. How do you calculate saturation from RGB?
2. Which of the following expression is correct for conversion of RGB values to saturation of HSI model?
3. Why do we convert RGB to HSI?

How do you calculate saturation from RGB?

The formula for Saturation uses the Min(RGB), Max(RGB) values and Luminosity. We have calculated the Luminosity before, L = 0,555. Our formula will be (A) as L = 0,555 < 1. We also know Max(RGB) = 0,898 and Min(RGB) = 0,212.

Which of the following expression is correct for conversion of RGB values to saturation of HSI model?

Equations to Convert RGB Values to HSI Values

I = (R + G + B)/3.

Why do we convert RGB to HSI?

R, G, B in RGB are all co-related to the color luminance( what we loosely call intensity),i.e., We cannot separate color information from luminance. HSV or Hue Saturation Value is used to separate image luminance from color information. This makes it easier when we are working on or need luminance of the image/frame.