Image of the absolute conic
HZ 7.5.1:
mapping between p to an image is given by the planar
homogaphy x=Hd, with H=KR
image of the absolute conic (IAC)  = I
(i) IAC depends only on intrinsics
(ii) angle between two rays
(iii) DIAC=w*=KKT
(iv)  w Û K (cholesky factorisation)
(v) image of circular points