what is skin color callibration or projecting skin pixel in 2d space ?

i am trying to implement hand gesture recognition , in that skin color calibration is said to be done . what is it ? and it also says " skin pixels of the calibration image are projected into the used 2D space and Skin color model is constructed by fitting the distribution of pixels in the color space by a tilted ellipse " .. how do i do that ?

Answer 1

[Image Analyst]

Like I said in your duplicate question they're getting the gamut in some color space, like HSV and saying that any pixel within some ellipsoid should be considered skin.