HSV color model

Perceptual colour space is an alternative way of representing true colour images in a manner that is more natural to the human perception and understanding of colour than the RGB representation. The Hue, Saturation and Value (HSV) colour space is popular in image analysis applications.
 
Changes within this colour space follow a perceptually acceptable colour gradient. From an image analysis perspective, it allows the separation of colour from lighting to a greater degree.
 
Each of these three parameters can be interpreted as follows:

1) H (hue) : is the dominant wavelength of the colour, e.g. red, blue, green
2) S (saturation) : is the ‘purity’ of colour (in the sense of the amount of white light mixed with it)
3) V (value) : is the brightness of the colour (also known as luminance).
 
Model for HSV color model :
 

An RGB image can be transformed into an HSV colour space representation as shown in Following Image: