A general rank-2 parameterization of the fundamental matrix

All the methods for estimating the fundamental matrix do not naturally exploit the rank-2 constraint. For this reason few rank-2 parameterizations of the fundamental matrix have been proposed over the years. In general they can be an over parameterization (12 parameters) being generally valid, or use a minimal set of parameters (eight) but do not cover all the rank-2 matrices. We propose a rank-2 parameterization which uses only 9 parameters, one more of the minimal parameterizations, and covers all the rank-2 matrices