 
  
  
   
We will compute the new PPMs,   and
  and   as the solution of a system of equations, which
express the constraints arising from rectification requirements plus
others constraints necessary to ensure a unique solution.
  as the solution of a system of equations, which
express the constraints arising from rectification requirements plus
others constraints necessary to ensure a unique solution.
In the following, we will denote with    the old PPMs. Let
  the old PPMs. Let
  
 
be the sought rectifying PPMs.