- Let
be a homography between two images through a
plane
. Thus we have (projectively)
- Given we know and .
- Now if
is
a valid decomposition, then so is
, where
- Thus, the most general projection matrices consistent with
are
and
- The matrix
is a projective
transformation of the plane
represented by the four vector
, since for points on this plane
, and
- Thus, the choice of corresponds to which actual plane in 3-space is .

Subhashis Banerjee 2008-01-21