Computing : I Number of Correspondences Given perfect image points (no noise) in general position. Each point correspondence generates one constraint on .
This can be rearranged as where is a measurement matrix, and is the fundamental matrix represented as a 9-vector.
Suppose the 9-vectors and , corresponding to the matrices and respectively, span the null-space. Then, up to scale, there is a one-parameter family of matrices: . Imposing
which is a cubic in , and thus has either one or three real solutions.